Use the Punnett square to predict the genotype for the parent organism whose genotype is unknown and
explain why it is the predicted genotype

The parent organism whose genotype is unknown is heterozygous for purple colour with genotype Ff.

Explanation: The parent organism whose genotype is unknown has a genotype Ff. If (F) represents the allele for purple colour and it is dominant over the allele for white colour (f), a cross between (Ff) and (ff) will produce Ff, Ff, ff and ff. Two of the offsprings are heterozygous for purple colour the other two are white.

Ff x ff = Ff, Ff, ff and ff. Ff will manifest as purple colour because F is dominant over f while ff will manifest as white because f is recessive.

See the attached punnet square for further information